In multistage rotary machines used for energy conversion, a fluid is used to produce rotational motion. In a gas turbine engine, for example, a gas is compressed in a compressor and mixed with a fuel source in a combustor. The combination of gas and fuel is then ignited for generating combustion gases that are expanded through a turbine to produce rotational motion. Both the turbine stage(s) and the compressor have stationary or non-rotary components, such as vanes, for example, that cooperate with rotatable components, such as rotor blades, for example, for compressing and expanding the operational gases.
As temperatures within the machines become substantially high, it is important to cool components of the machine to prevent overheating that could lead to decreased performance, inefficiency, and/or failure, including melting. During development of the machines, cooling air passages are formed through shrouds that are affixed to the vanes and/or rotor blades. The air passages are used to transfer cooling air to areas of the vanes and/or rotor blades which are to be cooled. Typically, when these cooling air passages are formed in the shrouds, a crossfeed aperture may be formed in an end portion of the shroud. These apertures are subsequently sealed to prevent an escape of the cooling air.
A known prior art technique for sealing these apertures by welding or brazing procedures can be time consuming. Such welding and brazing procedures can result in excess welding or brazing material being deposited in the cooling air passages. Once in the cooling air passages, this material can harden and subsequently limit cooling air flow causing inadequate cooling of the parts. Further, applying welding or brazing material to close off the apertures can adversely affect shroud machining operations, such as seal slot electrical discharge machining, in that the welding or brazing material may be harder and consequently less conducive to further machining operations.
In view of the foregoing considerations it would be desirable to provide a plug for use in a shroud of a rotary machine, whereby the plug can be mechanically affixed in shroud crossfeed apertures, and wherein the plug permits performance of follow-up shroud machining operations.